1. Technical Field
The present invention relates to a test apparatus and a test method for testing a device under test.
2. Related Art
A test apparatus for testing a semiconductor device or the like includes one or more test units and a control apparatus. Each test unit supplies a test signal to the device under test.
The control apparatus can be realized as a computer connected to the test units via a serial communication cable or the like. The control apparatus issues an access request to each of the test units to control the test units. The access request issued by the control apparatus is stored temporarily in a buffer, and is then transmitted to the test units via a bus or the like.
When clearing the buffer, the control apparatus issues a read request to the test units and does not issue a new access request until receiving a response to this read request. As a result, the access requests that were issued before the read request are pushed out of the buffer to the test units, thereby clearing the buffer. When a read request has been issued, the control apparatus must be in a standby state not performing other processes until receiving the response to the read request.
In recent test apparatuses, however, the test units supplying test signals to the devices under test are controlled from remote control apparatuses. As a result, the total time from when a control apparatus issues a read request to when the response is received is increased. Accordingly, the standby time of a control apparatus when clearing access requests from a buffer is increased.